More efficient structural cell for facilitating tree root growth

Abstract

A structural cell system for supporting hardscape, allowing tree root growth, and managing stormwater underneath the hardscape. The system may include: a base having a plurality of receptacles and a plurality of support members interconnecting the receptacles; a plurality of legs each sized and shaped to be attachable to the base within one of the receptacles so as to extend from the base, and to be attachable to another of the legs so that pairs of legs attached to each other collectively extend from the base; and a top attachable to the legs. Outer edges of the base, the top, and the legs attached thereto define a volume, and are configured to support at least that portion of the hardscape overlying the top as well as a commercial vehicle traffic load thereon, while maintaining soil in a substantially uncompacted state throughout at least approximately ninety percent of the volume.

What is claimed is: 
     
       1. A method comprising:
 placing a plurality of structural cells so that the structural cells are adjacent to each other; 
 wherein each structural cell comprises: 
 a base having a plurality of receptacles and a plurality of support members interconnecting the receptacles; 
 a top; and 
 a plurality of legs affixing the base to the top; 
 wherein outer edges of the base, the top, and the legs affixed thereto define a volume, and are configured to support at least that portion of a hardscape overlying the top as well as a traffic load thereon, and ninety percent or more of the defined volume is free volume, 
 wherein each receptacle is connected to the top by a pair of interconnected ones of the legs, each pair of interconnected ones of the legs comprising a first leg having a first length and a second leg having a second length, the first length being greater than the second length. 
 
     
     
       2. The method of  claim 1 , further comprising:
 filling the cells with a substantially loosely compacted soil, so as to allow roots of the tree to grow into the soil within the structural cells while simultaneously providing storage and pollutant removal of stormwater. 
 
     
     
       3. The method of  claim 2 , wherein the filling the cells further comprises filling the cells with material layers so as to form a bioretention system within the cells, each of the material layers being substantially uncompacted so as to allow roots of the tree to grow into the bioretention system within the cells. 
     
     
       4. The method of  claim 1 , wherein outer edges of the receptacles extend beyond outer edges of the support members. 
     
     
       5. The method of  claim 1 , wherein the base and the legs each comprise an unreinforced plastic. 
     
     
       6. The method of  claim 5 , wherein the unreinforced plastic is high density polyethylene (HDPE). 
     
     
       7. The method of  claim 1 , wherein the base, the top, and the legs attached thereto are sized and shaped to support a load of at least approximately 15 psi across substantially the entire top. 
     
     
       8. The method of  claim 1 , wherein:
 at least two of the receptacles lie along a first direction, and at least two of the receptacles lie along a second direction different from the first direction; and 
 each of the legs has a cross-sectional shape having protrusions, the protrusions arranged so that, when each of the legs is attached to a receptacle, its protrusions extend in the first and second directions. 
 
     
     
       9. The method of  claim 1 :
 wherein the base is configured so that plural ones of the bases are stackable in a vertical direction so as to be substantially coupled in a lateral direction perpendicular to the vertical direction, and so as to be substantially uncoupled in the vertical direction; and 
 wherein the top is configured so that plural ones of the tops are stackable in the vertical direction so as to be substantially coupled in the lateral direction and substantially uncoupled in the vertical direction.